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Vacuum packed
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THE LAST WORD No stone unthrown Personal experience suggests that if you put human males beside a body of water with a supply of stones to hand, they will soon start throwing them into the water. What drives them to do this, and is the same true of females? Is this unique to humans, or has it been observed in other primates? What purpose can it possibly serve?
throw rocks at zoo visitors. Some bonobos throw rocks at their preferred male to indicate they’re ready to mate. However, heaving stones into water with no obvious hunting intent seems to be the preserve of Homo sapiens. Some theorise that this is a fish-hunting activity but, if so, the results are abysmal. Given some rocks, water and nothing else to do, humans quickly become competitive, battling to see who can make the largest splash, skip a flat rock the furthest or hit a floating target. This clearly
n I have just listened to a radio programme by David Attenborough about the aquatic ape theory, and it strikes me that this question fits “Many primates throw well with this hypothesis. rocks, faeces and sticks Thinking of our environment, and some chimps throw we struggle to picture the land or them at visitors to zoos” sea in pre-industrial times when both were teeming with animals. Our distant shore-living ancestors provides hunting practice, would have been constantly but is also classic play behaviour, scanning the water for fish or think cats and their prey. other marine food animals, and The “nothing else to do” lobbing stones would surely have factor is important, and also been a simple way of killing a few. suggests play behaviour. Maybe the skill was translated Ron Dippold to throwing slings, boomerangs, San Diego, California, US spears and so on when humans later made hunting excursions further inland. Round and about Since young men would People of my generation (I am 75) can naturally compete against one remember when hens’ eggs used to another with their hunting skills, have a rounded end and a pointy end. males skimming stones seems another argument for the aquatic Now the ends seem much more alike. Have eggs changed over the years, ape theory. and if so, why? Stella Perrett Bristol, UK n Most eggs still have a round end and a pointy end – indeed, n Many primates throw rocks, a quick survey of eggs from faeces and sticks, and some battery hens in my local chimps have been known to
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
supermarket revealed 100 per cent normal eggs, although just what is egg-shaped is open to debate. Any spherical or nearspherical eggs are most likely a result of severe inbreeding. The majority of commercial egg-laying chickens are ISA Brown hens – ISA standing for Institut de Sélection Animale – which have been specifically bred for maximum egg production. These birds are now found across the world and frequently exhibit genetic faults previously found only in obscure textbooks. My purebred Wyandotte chickens lay “normal-shaped” eggs, with each hen laying a shape that is distinctly her own. The eggs get bigger during the laying period (between three and five days is normal) as the thickness of the shell decreases and its radius of curvature increases. This affects shell strength and means that eggs laid later are fatter, though never spherical. After the laying period, the hen will take a break of up to two days and begin again. Battery fowl kept in heated environments with controlled lighting will have a laying period of up to three weeks before taking a short break. Eggs pass along the oviduct “pointy” end first. If the hen is not frightened or interrupted, it will rotate the egg horizontally in the cloaca just before laying so that the egg is expelled round end first. If the bird is disturbed, the egg will
be forced through pointy end first. The egg is laid with a soft shell that hardens rapidly in contact with the air. Nina Dougall Malmsbury, Victoria, Australia
This week’s questions Stoned again
Your question about throwing stones (above) leads me on to another. I am left-handed, but like many of us in this back-to-front world I can do most things fairly well right-handed. Yet when it comes to throwing overarm or skimming stones, I can only do it right-handed and not with my dominant hand at all. Does anyone know why this might be? Bryan Simmons Westbury, Wiltshire, UK Vacuum packed
The OSIRIS-REx mission to the asteroid Bennu will gather samples using a robotic arm equipped with a vacuum cleaner. How does a vacuum cleaner work in the vacuum of space? Douglas Lee Glasgow, UK, and Tony Lamont Townsville, Queensland, Australia Sleeping sickness
Being sedentary is one of the causes of deep vein thrombosis. So why don’t we get DVTs in our sleep? Cormac Byrne London, UK
THE LAST WORD No stone unthrown Personal experience suggests that if you put human males beside a body of water with a supply of stones to hand, they will soon start throwing them into the water. What drives them to do this, and is the same true of females? Is this unique to humans, or has it been observed in other primates? What purpose can it possibly serve?
throw rocks at zoo visitors. Some bonobos throw rocks at their preferred male to indicate they’re ready to mate. However, heaving stones into water with no obvious hunting intent seems to be the preserve of Homo sapiens. Some theorise that this is a fish-hunting activity but, if so, the results are abysmal. Given some rocks, water and nothing else to do, humans quickly become competitive, battling to see who can make the largest splash, skip a flat rock the furthest or hit a floating target. This clearly
n I have just listened to a radio programme by David Attenborough about the aquatic ape theory, and it strikes me that this question fits “Many primates throw well with this hypothesis. rocks, faeces and sticks Thinking of our environment, and some chimps throw we struggle to picture the land or them at visitors to zoos” sea in pre-industrial times when both were teeming with animals. Our distant shore-living ancestors provides hunting practice, would have been constantly but is also classic play behaviour, scanning the water for fish or think cats and their prey. other marine food animals, and The “nothing else to do” lobbing stones would surely have factor is important, and also been a simple way of killing a few. suggests play behaviour. Maybe the skill was translated Ron Dippold to throwing slings, boomerangs, San Diego, California, US spears and so on when humans later made hunting excursions further inland. Round and about Since young men would People of my generation (I am 75) can naturally compete against one remember when hens’ eggs used to another with their hunting skills, have a rounded end and a pointy end. males skimming stones seems another argument for the aquatic Now the ends seem much more alike. Have eggs changed over the years, ape theory. and if so, why? Stella Perrett Bristol, UK n Most eggs still have a round end and a pointy end – indeed, n Many primates throw rocks, a quick survey of eggs from faeces and sticks, and some battery hens in my local chimps have been known to
The writers of answers that are published in the magazine will receive a cheque for £25 (or US$ equivalent). Answers should be concise. We reserve the right to edit items for clarity and style. Please include a daytime telephone number and an email address if you have one. New Scientist retains total editorial control over the published content. Reed Business Information Ltd reserves all rights to reuse all question and answer material that has been
submitted by readers in any medium or in any format and at any time in the future. Send questions and answers to The Last Word, New Scientist, 110 High Holborn, London WC1V 6EU, UK, by email to [email protected] or visit www.newscientist.com/topic/lastword (please include a postal address in order to receive payment for answers). Unanswered questions can also be found at this URL.
supermarket revealed 100 per cent normal eggs, although just what is egg-shaped is open to debate. Any spherical or nearspherical eggs are most likely a result of severe inbreeding. The majority of commercial egg-laying chickens are ISA Brown hens – ISA standing for Institut de Sélection Animale – which have been specifically bred for maximum egg production. These birds are now found across the world and frequently exhibit genetic faults previously found only in obscure textbooks. My purebred Wyandotte chickens lay “normal-shaped” eggs, with each hen laying a shape that is distinctly her own. The eggs get bigger during the laying period (between three and five days is normal) as the thickness of the shell decreases and its radius of curvature increases. This affects shell strength and means that eggs laid later are fatter, though never spherical. After the laying period, the hen will take a break of up to two days and begin again. Battery fowl kept in heated environments with controlled lighting will have a laying period of up to three weeks before taking a short break. Eggs pass along the oviduct “pointy” end first. If the hen is not frightened or interrupted, it will rotate the egg horizontally in the cloaca just before laying so that the egg is expelled round end first. If the bird is disturbed, the egg will
be forced through pointy end first. The egg is laid with a soft shell that hardens rapidly in contact with the air. Nina Dougall Malmsbury, Victoria, Australia
This week’s questions Stoned again
Your question about throwing stones (above) leads me on to another. I am left-handed, but like many of us in this back-to-front world I can do most things fairly well right-handed. Yet when it comes to throwing overarm or skimming stones, I can only do it right-handed and not with my dominant hand at all. Does anyone know why this might be? Bryan Simmons Westbury, Wiltshire, UK Vacuum packed
The OSIRIS-REx mission to the asteroid Bennu will gather samples using a robotic arm equipped with a vacuum cleaner. How does a vacuum cleaner work in the vacuum of space? Douglas Lee Glasgow, UK, and Tony Lamont Townsville, Queensland, Australia Sleeping sickness
Being sedentary is one of the causes of deep vein thrombosis. So why don’t we get DVTs in our sleep? Cormac Byrne London, UK